Security systems and home automation networks are described in numerous patents, and have been in prevalent use for over 40 years. In the United States, there are over 14 million security systems in residential homes alone. The vast majority of these systems are hardwired systems, meaning the keypad, system controller, and various intrusion sensors are wired to each other. These systems are easy to install when a home is first being constructed and access to the interiors of walls is easy; however, the cost increases substantially when wires must be added to an existing home. On average, the security industry charges approximately $75 per opening (i.e., window or door) to install a wired intrusion sensor (such as a magnet and reed switch), where most of this cost is due to the labor of drilling holes and running wires to each opening. For this reason, most homeowners only monitor a small portion of their openings. This is paradoxical because most homeowners actually want security systems to cover their entire home.
In order to induce a homeowner to install a security system, many security companies will underwrite a portion of the costs of installing a security system. Therefore, if the cost of installation were $1,500, the security company may only charge $500 and then require the homeowner to sign a multi-year contract with monthly fees. The security company then recovers its investment over time. Interestingly enough, if a homeowner wants to purchase a more complete security system, the revenue to the security company and the actual cost of installation generally rise in lockstep, keeping the approximate $1,000 investment constant. This actually leads to a disincentive for security companies to install more complete systems—it uses up more technician time without generating a higher monthly contract or more upfront profit. Furthermore, spending more time installing a more complete system for one customer reduces the total number of systems that any given technician can install per year, thereby reducing the number of monitoring contracts that the security company obtains per year.
In order to reduce the labor costs of installing wired systems into existing homes, wireless security systems have been developed in the last 10 to 20 years. These systems use RF communications for at least a portion of the keypads and intrusion sensors. Typically, a transceiver is installed in a central location in the home. Then, each opening is outfitted with an intrusion sensor connected to a small battery powered transmitter. The initial cost of the wireless system can range from $25 to $50 for each transmitter, plus the cost of the centrally located transceiver. This may seem less than the cost of a wired system, but in fact the opposite is true over a longer time horizon. Wireless security systems have demonstrated lower reliability than wired systems, leading to higher service and maintenance costs. For example, each transmitter contains a battery that drains over time (perhaps only a year or two), requiring a service call to replace the battery. Further, in larger houses, some of the windows and doors may be an extended distance from the centrally located transceiver, causing the wireless communications to intermittently fade out. In fact, the UL standard for wireless security systems allows wireless messages to be missed for up to 12 hours before considering the missed messages to be a problem. This implies an allowable error rate of 91%, assuming a once per hour supervisory rate.
These types of wireless security systems generally operate under 47 C.F.R. 15.231(a), which places limits on the amount of power that can be transmitted. For example, at 433 MHz, used by the wireless transmitters of one manufacturer, an average field strength of only 11 mV/m is permitted at 3 meters (equivalent to approximately 36 microwatts). At 345 MHz, used by the wireless transmitters of another manufacturer, an average field strength of only 7.3 mV/m is permitted at 3 meters (equivalent to approximately 16 microwatts). Control or supervisory transmissions are only permitted once per hour, with a duration not to exceed one second. If these same transmitters wish to transmit data under 47 C.F.R. 15.231(e), the average field strengths at 345 and 433 MHz are reduced to 2.9 and 4.4 mV/m, respectively. The current challenges of using these methods of transmission are discussed in various patents, including U.S. Pat. Nos. 6,087,933, 6,137,402, 6,229,997, 6,288,639, and 6,294,992.
Some security systems combine cellular telephone, alarm monitoring, and signal transmission functions. For example, U.S. Pat. No. 5,568,535 issued to Sheffer et al. discloses an alarm system for protecting premises having a fully integrated, alarm-detecting cellular phone unit which is linked to various sensors in order to detect the sensor outputs. The cellular alarm unit includes, in addition to cellular phone functions, a formatter or processor for generating an emergency signal on detection of a sensor output. The emergency signal includes information on the type of emergency detected. The unit is programmed to establish a cellular connection to a remote monitoring station. The connection is wireless at least from the premises to a local cell site. Once connection is established, the emergency signal is transmitted to the monitoring station via the local cell site.
U.S. Pat. No. 5,745,849 issued to Britton discloses a combination cordless telephone and premise-monitoring alarm system. The combination has a base unit, a cordless handset, and one or more remote alarm detectors. The alarm detectors can be generally either smoke detectors, motion detectors, or open-entry detectors. The base unit includes at least one interface for the public telephone network, and another interface for radio communication with the cordless handset. The base unit preferably also communicates with the remote alarm sensors across the same radio interface. The base unit includes telephone call circuitry to relay telephone calls between the public telephone network and the handset. The base unit also includes alarm processing circuitry to send an alarm warning to a central alarm-monitoring station in response to an alarm signal from a remote detector. The base unit has control circuitry that is configured such that if, during a telephone call, the base unit is given an alarm signal, the base unit will either (i) hang up the telephone call and contact the central alarm-monitoring station to give a warning, or (ii) call up the central alarm-monitoring station on a second telephone line (if available).
In either wired or wireless prior art security systems, additional sensors such as glass breakage sensors or motion sensors are an additional cost beyond a system with only intrusion sensors. Each glass breakage or motion sensor can cost $30 to $50 or more, not counting the labor cost of running wires from the alarm panel to these sensors. In the case of wireless security systems, the glass breakage or motion sensor can also be wireless, but then these sensors suffer from the same drawback as the transmitters used for intrusion sensing—they are battery powered and therefore require periodic servicing to replace the batteries and possible reprogramming in the event of memory loss.
Because existing wireless security systems are not reliable and wired security systems are difficult to install, many homeowners forego self-installation of security systems and either call professionals or do without. It is interesting to note that, based upon the rapid growth of home improvement chains such as Home Depot and Lowe's, there is a large market of do-it-yourself homeowners that will attempt carpentry, plumbing, and tile—but not security. There is, therefore, an established need for a security system that is both reliable and capable of being installed by the average homeowner.
Regardless of whether a present wired or wireless security system has been installed by a security company or self-installed, almost all present security systems are capable of only monitoring the house for intrusion, fire, or smoke. These investments are technology limited to a substantially single purpose. There would be a significant advantage to the homeowner if the security system were also capable of supporting additional home automation and lifestyle enhancing functions. There is, therefore, an apparent need for a security system that is actually a network of devices serving many functions in the home. It is therefore an object of the present invention to provide security system for use in residential and commercial buildings that can be self-installed or installed by professionals at much lower cost than present systems.
More specific objects of the present invention are directed to the inclusion of a portable cordless telephone handset into the security network. An object of the present invention is to integrate a base unit, a gateway, or both into the charging cradle for the cordless telephone handset or into a related console for the charging cradle and handset. Related objects are to require fewer outlets as compared with separate security and cordless telephony systems; minimize the probability of interference between two separate systems; integrate control of the security network into a familiar device, namely a portable cordless telephone handset; allow the user to carry the handset to each transponder (and their associated sensors) as each is installed and configured during the registration process; and distribute multiple charging cradles with integrated RFID readers around the building to be monitored to achieve spatial separation and improved wireless coverage for both security and telephony as a matter of course.
Another object of the present invention is to overcome environmental effects such as multipath and signal blockage. It is still another object of the present invention to provide redundancy in the event of a single component failure. A further object of the present invention to provide a portable cordless telephone handset that incorporates a number of helpful functional features, such as distributed weight; predetermined dimensions that facilitate handling by a variety of users; keys colored, textured, sized, or shaped to provide information to the user; a cover protecting a panic key; and recessed keys to avoid inadvertent contact.
Additional objects and advantages of this invention will be apparent from the following detailed description.